Comments

3.5.7.6 -stable review patch. If anyone has any objections, please let me know.
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From: Alan Stern <stern@rowland.harvard.edu>
commit ee74290b7853db9d5fd64db70e5c175241c59fba upstream.
This patch (as1652) fixes a long-standing bug in ehci-hcd. The driver
relies on status polls to know when to stop port-resume signalling.
It uses the root-hub status timer to schedule these status polls. But
when the driver for the root hub is resumed, the timer is rescheduled
to go off immediately -- before the port is ready. When this happens
the timer does not get re-enabled, which prevents the port resume from
finishing until some other event occurs.
The symptom is that when a new device is plugged in, it doesn't get
recognized or enumerated until lsusb is run or something else happens.
The solution is to re-enable the root-hub status timer after every
status poll while a port resume is in progress.
This bug hasn't surfaced before now because we never used to try to
suspend the root hub in the middle of a port resume (except by
coincidence).
Signed-off-by: Alan Stern <stern@rowland.harvard.edu>
Reported-and-tested-by: Norbert Preining <preining@logic.at>
Tested-by: Ming Lei <ming.lei@canonical.com>Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>Signed-off-by: Herton Ronaldo Krzesinski <herton.krzesinski@canonical.com>
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drivers/usb/host/ehci-hub.c | 6 +++++-
1 file changed, 5 insertions(+), 1 deletion(-)